Antistain baths for sensitive color photographic material



duce a negative image.

Patented Oct. 4, 1949 UNITED STATES ANTISTAIN BATHS FOR SENSITI VE COLOR PHOTOGRAPHIC MATERIAL Harold C. Harsh and James E. Bates, Binghamton, N. Y., assignors to General Aniline & Film. Corporation, New York, N. Y., a corporation .of

Delaware No Drawing. Application November 18, 1947,

Serial No. 786,808 a This invention relates to photographic antistain baths, to anti-stain baths employed in multi-color photography, and especially to nonstaining baths for the washing of multi-color photographic material following the bleaching and fixing treatment.

It is known that in the processing of multi-color reversible film and multi-color reversible film coated upon a white opaque support, the exposed film or exposed white opaque, is first developed with a normal black and white developer to pro- After development, the black and white negative material, without being fixed, is exposed to general illumination, followed by a second development with a color-forming developer. During the first and second development, the silver-halides in all the layers are reduced to metallic silver. After the second development, the material is cleared in running water, hardened in an aqueous solution consisting of either alumor potassium chrome, and then washed in running water. After the latter treatment, the silver present in all the layers formed during the first and second development is converted into a saltby any of the known silver-salt formers, commonly known as bleaching baths, and the silver salt thus formed is then removed by dissolving it in a silver-salt solvent such as, for example, hypo. The material is then washed for a long period of time and then dried.

Prior to the final washing operation it is essential that the residual second or color developer and bleach solutions be removed, otherwise stains will be formed during the drying operation, which are particularly noticeable in the white area. In order to prevent this staining, an extended'washing time in running water of from fifteen minutes to two hours, has been proposed.

Even if this proposal be adopted, stains are nevertheless formed after the drying operation. It is 1 Claim. (Cl. 95-88) 2 become more apparent as the description proceeds.

We have found that the above objects are accomplished by employing, as a final rinse bath, an aqueous solution containing a small quantity of boric acid. The concentration of the boric acid may vary from as little-as 0.01% to 1%. Amounts higher than 1% give little improvement in stain prevention from a practical standpoint and, accordingly, concentrations ranging from between 0.05% to 0.5% are most desirable.

The photographic multi-layer materials, which may be processed with the anti-stain bath of the present invention, are color reversible film, color negative film, color reversible printing material coated on a white opaque base, and color paper, irrespective of whether the dyestufi images are produced with color-formers present in the emulsion or by a selective seond exposure followed by color development. The color reversible film consists of an integral tripack emulsion coated on the usual clear cellulose acetate or nitrate film base. Each of the emulsions are sensitized to one of the primary colors of light; namely, blue, green, and red. 'The top layer is blue sensitive. A filter layer, yellow in color and blue absorbing, lies under the top layer. Below this filter layer, lies a green sensitive emulsion layer, and below this is a red sensitive emulsion layer. Each of the three silver-halide emulsion layers vcontain dyeforming compounds which unite during the development of silver image in an aromatic amine developing agent to form a dye with the oxidation productof the developing agent, or may be free from color-formers, in which case the film is processed with the color-formers in the color developers by the selective second exposure and color development method as described in United States Patents 1,897,866; 1,900,870; 1,928,709 and 1,980,941. The color negative film is made up in the same manner as the color reversible film,

with the exception that it may contain a layer of clear gelatin between the red sensitive layer and the green sensitive layer. The color reversible white opaque material is prepared in the same manner as color reversible film and the color negative film, with the exception that the base consists of an opaque white film. The color paper is also constructed in the same manner as the color reversible film and the color negative film,

with the exception that the emulsion is coated on a baryta coated paper base.

As silver is formed during development, it must be removed after color development by treatment in a bleach, followed by treatment in a bath of sodium thiosulfate according to usual practice. A yellow dye is formed in the blue sensitive emulsion; a magenta dye is formed in the green sensitive emulsion; and a cyan dye is formed in the red sensitive emulsion. Combinations of; these three printing primaries will produce. all of the other colors in the finished film or print. Suitable methods for the preparation of photographicmulti-layer materials have been described in the literature relating to color photography, and: are; therefore, not described here.

The following examples descri-bain detaihmethods for accomplishing the above objectmbut it; is

to be understood that they are inserted merely.- for purposes of illustration and are not to be construed as limiting the scope of theinvention- Example I A 4" x 5" full color transparency sheet ofcolor film was printed by contact on two 4" x 5" sheets of'colo'r reversible white opaque film.

The two sheets of 4." x 5." color reversible white opaque film were'first developed for twelve minutes. at 68 F. in a developer of the following composition:

p-Monomethylamine-m-phenol sulfate grams 3 Sodium sulfite doe--- 50 Hydroquinone do 6 Sodium carbonate (-monohydr-ate) do 40 Sodium thiocyanate do 2 Potassium bromide do 2 Water to makeup liter 1 Thedevelopedfilm was short stopped for 3 minutes at. 68 F., in a 5% aqueous solution of sodium bisulfite.

Thefilm was washed for 2 minutes in running water at 68 F., and then color developed for 15 minutes. at 63 F., ina developer of the following composition:

p-Ami'nodiethylaniline HCl' grams 4 Sodium sulfite do 20 Hydroxylamine HCl' do 1 Sodium carbonate do 80 Potassium bromide do 1 Water to make up liter 1' The color developed-film was rinsed for Lmirrutes in: running waterat' 68? F.', and hardened for 5 minutes inla 3% aqueous solution of potassium chrome alum.

The hardened film: was washed for 5: minutes im runninglwater at 685" F. The washed material was then treated with a bleach bath of the following: composition:

Di-potassium mono-sodium ferricyanide grams" 100 Potassium bromide do 15- Disodium phosphate do 40 Sodium bisul-fate do 2 5 Formalin oc 20 Water to make u-pliter 1 The bleached film was washed for 5 minutes at 68 F., and then fixed for 5 minutes in a solutiorr of the following composition:

Hypo grams 200 Bbrax' do 10 Water to make liter -1 After fixing, the material. was washed for 10 minutes. irrrunning water at 68 F.

After the final waslr, one-print was allowed to the: print rinsed; imboric acid solution did not change.

Ebzample II A2 4" x 2%." color negative film was printed by projection on two 4 x 5" sheets of multilayer photographic color paper.

The two 4" x 5" sheets of color paper were developed for 8 minutes. at 68 F. in a developer oil the following; compositions p-Aminodiethylaniline'HCL gramsz- 3,25 Sodium sulfite do 20} Sodium carbonate"; do Potassium bromide do" I; Hydroxylamine HCl do; 2 Water to make up liter' 1 The developed film: was=shortstoppedlfor'fiimim utes-at 68 F1 in a batliof the fo'llowing, composi-- tion: 1

Ox-a-lic acid grams 15. Potassium metabisulfitewflwnuu do 15 Potassium. oxalatefin do 60, Sodium sulfate d do 20. Water to makeup liter 1.

and then bleached for 5 minutes in a; bleach bathof thefollowing' composition:

Potassium ferricyanide grams- 30 Potassium bromide. do 10 water-to-make-up e litere I;

The film was washedfor'5. minutes at 68. F. and then fixed for 5' minutes in a solution of the following composition:

Hypo grams 200 B'orax' do 5 Water to make up liter; 1

After fixing, the material; was washed for 30.- minutes in runningwater at 68 B.

After the final wash, one printwasallowed to. dry while the other was rinsed for Z-minutes in-a 0.1% solution. of: boric acid andallowedto dry. At this point, the.printsappeamad-identical.v After. normal.- dryin-gthe print rinsed in the looriaacidsolution showed: brighter colors. and more br-illiant. highIig-htsthan: the print given onlya water wash-for 30 minutes.

Example-I was repeated with-theexceptionthat the final rinse bath was a .01 solutionof; bor-ic acid instead ofa 0.1%; solution Afterfixing and washing, the. color print rinsed. in plain. water. showed objectionable-stains, while the. print treat! ed with the boric acid solution wasclear andiunstained.

From the above exampies it is manifest: that the multi-layer photographicmaterial ri'nsed in plain water shows marked staining upon drying of said material. This staining occurs especially under slow drying conditions; and is: probably due to the coupling of the slow oxidation product of the color developer with a residual color-coupler present in one or more layers.

The above specific examples are to be regarded as merely illustrative of the invention and not in any sense restrictive.

This application is a continuation-in-part of our co-pending application Serial No. 627,534, filed November 8, 1945.

We claim:

In a process of producing color photographic images selected from the class consisting of indophenol and azomethine dyes in a color film having a plurality of silver halide emulsion layers by exposing the film, color developing the same, bleaching, fixing and washing, the improvement which comprises avoiding the formation of stain,

Number Name Date 1,930,140 Becker Oct. 10, 1933 15 1,981,391 Russell Nov, 20, 1934 2,367,516 Muehler et a1. Jan. 16, 1945 2,367,548 Vittum Jan. 16, 1945 6 after the bleaching, fixing, and washing operations, by rinsing the film with an aqueous solution consisting of water and boric acid in a concentration ranging from 0.01% to 1%.

r HAROLD C. HARSH.

JAMES E. BATES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PA'I'EN'IS 

